overdrive vs distortion

Im somewhat lost, can someone explain to me the difference between overdrive for bass, and distortion for bass, if there is any?
Im a huge rage fan, and i know timmy used alot of overdrive, but how can this be compared to distortion, or is it overdrive just bass with distortion?
sorry for the lame question.

It kind of depends...there are basically two ways to look at it. There is the more technical way, which, from what I've heard, goes like this: overdrive is characterized as "soft clipping"-where the signals range is slightly restricted-this can be achieved many of times by overloading the amp to a degree..."overdriving" it. Distortion is "hard clipping", where the range is severely restricted, and is purposely done, usually by the use of a pedal.

The two have similar tones and most pedals offer both tones in one pedal. In the regular sense, overdrive can be seen as softer distortion. A lot of people actually use the two interchangeably.

Overdrive, distortion and fuzz are often used interchangeably, but in a nutshell can be used to describe three degrees of the same effect: overdrive being a slightly grittier tone often heard in tube amps, distortion being a much dirtier tone while still retaining note definition, and fuzz tends to be a much more extreme distortion where note definition begins to be lost.

On a technical basis: overdrive refers to soft clipping, whereas the extremes of a sine wave are compressed a bit, distortion compresses them significantly more, and fuzz cuts off the tips. In the diagram below, overdrive and distortion are more characterized by the yellow, the red shows fuzz and the blue denotes the original signal.

Makes me want to bring my bass and ODB-3 to work, and see if the guys in the R&D Lab will let me have a little time alone with their $12,000 'scope! That thing does both time domain AND frequency domain, and saves screen dumps to disk, so we could look at a spectrum chart.

I might have to borrow a Lab Tech too if I want to bring-up the FFT functions - or I suppose I could look through the operation manual through a lunch or two - that thing looks like a phone book!